Combined Effect of Deccan Volcanism and the Chicxulub Asteroid for Biological Crisis and Ending of Mesozoic Era
Novel Perspectives of Geography, Environment and Earth Sciences Vol. 9,
18 August 2023
,
Page 171-187
https://doi.org/10.9734/bpi/npgees/v9/4293B
Abstract
This chapter reevaluates the accumulated information focuses on the response of individual taxa to the ecological perturbations that the Deccan volcanism and/or the asteroid impact might have inflicted on life on earth because none of their suggested physical and chemical hazardous factors could have resulted in the puzzling extinction-survival pattern. Radioisotopic constraints on Deccan-related volcanism are much less precise, but they show that early- and late-stage alkalic eruptions preceded and postdated Cretaceous-Paleogene time by at least several million years.
Their combined ejecta must have shaded the sunlight, ceasing photosynthesis for about 2-3 years and lowering the temperature on earth, which must have been crucial for cold-blooded reptiles. The darkening would have obscured seasonality, severely limiting flower blossoming, fruition, and creature reproduction. As a result, the marine and terrestrial food chains as well as prey-predator connections would have collapsed. Other than famine, the majority of the killing was done by the organisms due to a Darwinian battle for survival that resulted in a selective eradication of the temporally susceptible species. Those who managed to flee adapted to their new surroundings and lived. The disappearance of most of the Cretaceous carnivore reptiles enabled the survivors to fearlessly explore the Tertiary world and acclimatize to previously inaccessible habitats, which continuously shaped with the ongoing changes in the ecological and biological settings. The collapse of marine primary production and hence the food chain resulted in intensive predation among marine organisms and the elimination of those that could not withdraw into refuge sites. The Tertiary ecosystems' dynamic development sped up evolutionary processes, resulting in rapid diversification. Although they were the direct descendants of Cretaceous survivors, they were given a new taxonomic identity, and their ancestors were declared extinct, compounding the apparent "mass extinction" that occurred at the end of the Cretaceous.
- End-cretaceous biological crisis
- Deccan Province volcanism
- asteroid impact
- atmosphere darkening
- food-chain collapse
- natural selection